The present invention relates to a gas discharge laser.
It is known to use a pre-ionising electrode array in a gas-discharge laser to condition the gas to facilitate the discharge between the discharge electrodes or main electrodes of the laser. In particular, it is known to use a sliding spark array employing a linear series of pairs of electrode "pins" passing lengthwise along the discharge vessel of the laser and along which a spark passes progressively from one end of the series to the other, that is, from one pair of pins to the next in the series.
However, the arrangements of a sliding-spark array heretofore employed have not been as efficacious as could be wished for in promoting the discharge between the main electrodes and in preventing arcing of the main electrodes.